From 1edf67fc3f6b944935506146de02348afa1003ff Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Mon, 3 Dec 2018 12:06:50 -0800 Subject: [PATCH] intel/fs: Generate if instructions with inverted conditions MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Per-platform results were all over the place, so I have included all the results here. There is an important note at the bottom of the commit message. Skylake total instructions in shared programs: 15184683 -> 15184679 (<.01%) instructions in affected programs: 2786 -> 2782 (-0.14%) helped: 4 HURT: 0 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: 0.05% max: 0.84% x̄: 0.44% x̃: 0.44% 95% mean confidence interval for instructions value: -1.00 -1.00 95% mean confidence interval for instructions %-change: -0.96% 0.07% Inconclusive result (%-change mean confidence interval includes 0). total cycles in shared programs: 370961367 -> 370961173 (<.01%) cycles in affected programs: 205867 -> 205673 (-0.09%) helped: 5 HURT: 1 helped stats (abs) min: 1 max: 149 x̄: 39.60 x̃: 16 helped stats (rel) min: 0.02% max: 1.05% x̄: 0.45% x̃: 0.55% HURT stats (abs) min: 4 max: 4 x̄: 4.00 x̃: 4 HURT stats (rel) min: 0.03% max: 0.03% x̄: 0.03% x̃: 0.03% 95% mean confidence interval for cycles value: -93.01 28.34 95% mean confidence interval for cycles %-change: -0.82% 0.08% Inconclusive result (value mean confidence interval includes 0). Broadwell total instructions in shared programs: 15465366 -> 15465362 (<.01%) instructions in affected programs: 2799 -> 2795 (-0.14%) helped: 4 HURT: 0 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: 0.04% max: 0.84% x̄: 0.44% x̃: 0.44% 95% mean confidence interval for instructions value: -1.00 -1.00 95% mean confidence interval for instructions %-change: -0.96% 0.07% Inconclusive result (%-change mean confidence interval includes 0). total cycles in shared programs: 410938419 -> 410938531 (<.01%) cycles in affected programs: 566028 -> 566140 (0.02%) helped: 18 HURT: 17 helped stats (abs) min: 1 max: 16 x̄: 3.50 x̃: 1 helped stats (rel) min: <.01% max: 1.05% x̄: 0.13% x̃: <.01% HURT stats (abs) min: 1 max: 12 x̄: 10.29 x̃: 12 HURT stats (rel) min: <.01% max: 0.16% x̄: 0.08% x̃: 0.09% 95% mean confidence interval for cycles value: 0.31 6.09 95% mean confidence interval for cycles %-change: -0.10% 0.05% Inconclusive result (%-change mean confidence interval includes 0). Haswell total instructions in shared programs: 13749760 -> 13749759 (<.01%) instructions in affected programs: 2241 -> 2240 (-0.04%) helped: 1 HURT: 0 total cycles in shared programs: 385398913 -> 385398363 (<.01%) cycles in affected programs: 554914 -> 554364 (-0.10%) helped: 31 HURT: 1 helped stats (abs) min: 1 max: 453 x̄: 18.00 x̃: 6 helped stats (rel) min: <.01% max: 0.25% x̄: 0.03% x̃: 0.05% HURT stats (abs) min: 8 max: 8 x̄: 8.00 x̃: 8 HURT stats (rel) min: 0.06% max: 0.06% x̄: 0.06% x̃: 0.06% 95% mean confidence interval for cycles value: -45.88 11.51 95% mean confidence interval for cycles %-change: -0.05% -0.02% Inconclusive result (value mean confidence interval includes 0). Ivy Bridge total cycles in shared programs: 180663626 -> 180663881 (<.01%) cycles in affected programs: 472350 -> 472605 (0.05%) helped: 15 HURT: 30 helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 helped stats (rel) min: <.01% max: <.01% x̄: <.01% x̃: <.01% HURT stats (abs) min: 8 max: 10 x̄: 9.00 x̃: 9 HURT stats (rel) min: 0.06% max: 0.14% x̄: 0.10% x̃: 0.10% 95% mean confidence interval for cycles value: 4.21 7.12 95% mean confidence interval for cycles %-change: 0.05% 0.08% Cycles are HURT. Sandy Bridge total cycles in shared programs: 154568664 -> 154569225 (<.01%) cycles in affected programs: 356486 -> 357047 (0.16%) helped: 1 HURT: 31 helped stats (abs) min: 2 max: 2 x̄: 2.00 x̃: 2 helped stats (rel) min: 0.02% max: 0.02% x̄: 0.02% x̃: 0.02% HURT stats (abs) min: 4 max: 33 x̄: 18.16 x̃: 8 HURT stats (rel) min: 0.05% max: 0.23% x̄: 0.14% x̃: 0.10% 95% mean confidence interval for cycles value: 12.19 22.87 95% mean confidence interval for cycles %-change: 0.10% 0.16% Cycles are HURT. Iron Lake total instructions in shared programs: 8206589 -> 8206565 (<.01%) instructions in affected programs: 3024 -> 3000 (-0.79%) helped: 12 HURT: 0 helped stats (abs) min: 2 max: 2 x̄: 2.00 x̃: 2 helped stats (rel) min: 0.75% max: 0.83% x̄: 0.80% x̃: 0.80% 95% mean confidence interval for instructions value: -2.00 -2.00 95% mean confidence interval for instructions %-change: -0.82% -0.77% Instructions are helped. total cycles in shared programs: 187657428 -> 187656228 (<.01%) cycles in affected programs: 95748 -> 94548 (-1.25%) helped: 12 HURT: 0 helped stats (abs) min: 80 max: 120 x̄: 100.00 x̃: 100 helped stats (rel) min: 1.00% max: 1.66% x̄: 1.27% x̃: 1.21% 95% mean confidence interval for cycles value: -113.27 -86.73 95% mean confidence interval for cycles %-change: -1.43% -1.11% Cycles are helped. GM45 total instructions in shared programs: 5037569 -> 5037557 (<.01%) instructions in affected programs: 1521 -> 1509 (-0.79%) helped: 6 HURT: 0 helped stats (abs) min: 2 max: 2 x̄: 2.00 x̃: 2 helped stats (rel) min: 0.75% max: 0.83% x̄: 0.79% x̃: 0.79% 95% mean confidence interval for instructions value: -2.00 -2.00 95% mean confidence interval for instructions %-change: -0.83% -0.75% Instructions are helped. total cycles in shared programs: 128101478 -> 128100758 (<.01%) cycles in affected programs: 52746 -> 52026 (-1.37%) helped: 6 HURT: 0 helped stats (abs) min: 120 max: 120 x̄: 120.00 x̃: 120 helped stats (rel) min: 1.16% max: 1.66% x̄: 1.41% x̃: 1.41% 95% mean confidence interval for cycles value: -120.00 -120.00 95% mean confidence interval for cycles %-change: -1.70% -1.12% Cycles are helped. This change has almost no effect right now. However, removing this patch (but leaving the patch "nir/algebraic: Replace a bcsel of a b2f with a b2f(!(a || b))") after adding a patch that removes !(a < b) -> (a >= b) optimizations (like https://patchwork.freedesktop.org/patch/264787/) has the following results on Skylake: Skylake total instructions in shared programs: 15071022 -> 15089710 (0.12%) instructions in affected programs: 1022219 -> 1040907 (1.83%) helped: 1 HURT: 3937 helped stats (abs) min: 41 max: 41 x̄: 41.00 x̃: 41 helped stats (rel) min: 1.01% max: 1.01% x̄: 1.01% x̃: 1.01% HURT stats (abs) min: 1 max: 256 x̄: 4.76 x̃: 4 HURT stats (rel) min: 0.05% max: 11.18% x̄: 2.59% x̃: 2.60% 95% mean confidence interval for instructions value: 4.56 4.93 95% mean confidence interval for instructions %-change: 2.54% 2.64% Instructions are HURT. total cycles in shared programs: 369777134 -> 370092923 (0.09%) cycles in affected programs: 17516573 -> 17832362 (1.80%) helped: 115 HURT: 3624 helped stats (abs) min: 1 max: 1721 x̄: 81.18 x̃: 28 helped stats (rel) min: <.01% max: 10.74% x̄: 1.24% x̃: 0.65% HURT stats (abs) min: 1 max: 12640 x̄: 89.71 x̃: 54 HURT stats (rel) min: <.01% max: 28.24% x̄: 4.72% x̃: 4.52% 95% mean confidence interval for cycles value: 75.21 93.71 95% mean confidence interval for cycles %-change: 4.43% 4.64% Cycles are HURT. total spills in shared programs: 9450 -> 9442 (-0.08%) spills in affected programs: 166 -> 158 (-4.82%) helped: 2 HURT: 0 total fills in shared programs: 21115 -> 21094 (-0.10%) fills in affected programs: 438 -> 417 (-4.79%) helped: 2 HURT: 0 LOST: 1 GAINED: 0 Reviewed-by: Kenneth Graunke --- src/intel/compiler/brw_fs_nir.cpp | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/src/intel/compiler/brw_fs_nir.cpp b/src/intel/compiler/brw_fs_nir.cpp index 9ecfad99939..fb373e1757e 100644 --- a/src/intel/compiler/brw_fs_nir.cpp +++ b/src/intel/compiler/brw_fs_nir.cpp @@ -381,13 +381,30 @@ fs_visitor::nir_emit_cf_list(exec_list *list) void fs_visitor::nir_emit_if(nir_if *if_stmt) { + bool invert; + fs_reg cond_reg; + + /* If the condition has the form !other_condition, use other_condition as + * the source, but invert the predicate on the if instruction. + */ + nir_alu_instr *const cond = nir_src_as_alu_instr(&if_stmt->condition); + if (cond != NULL && cond->op == nir_op_inot) { + assert(!cond->src[0].negate); + assert(!cond->src[0].abs); + + invert = true; + cond_reg = get_nir_src(cond->src[0].src); + } else { + invert = false; + cond_reg = get_nir_src(if_stmt->condition); + } + /* first, put the condition into f0 */ fs_inst *inst = bld.MOV(bld.null_reg_d(), - retype(get_nir_src(if_stmt->condition), - BRW_REGISTER_TYPE_D)); + retype(cond_reg, BRW_REGISTER_TYPE_D)); inst->conditional_mod = BRW_CONDITIONAL_NZ; - bld.IF(BRW_PREDICATE_NORMAL); + bld.IF(BRW_PREDICATE_NORMAL)->predicate_inverse = invert; nir_emit_cf_list(&if_stmt->then_list); -- 2.30.2